Soluble fiber, dissolves in water. It delays gastric emptying which in turn can cause an extended feeling of fullness.

Insoluble fiber, does not dissolve in water. Bulking fibers absorb water as they move through the digestive system, easing defecation.

Some fiber rich sources are: Fruits, Vegetables, and Nut

Fruits: Mangoes, Apple, Pineapple etc

Vegetables: Broccoli, Carrots etc

Nuts: Almonds, Peanuts, Cashew

Fiber helps decrease high blood sugar levels.For example, if you eat a foods with high glycemic index it will spike your blood sugar and provide instant energy which if not used shortly will imbalance your insulin levels and will result in fat storage and in long run may result in diabetics.

How to fix it?

Easy add some fiber to your meals if you eat white rice eat some broccoli alongside or other fiber rich vegetables in moderate amount, additionally add some protein and healthy fats to your meals to keep your meals glycemic index low which will provide you with energy for long time.

Fiber is good for body building because it helps with digestion and helps you digest well and intern support an environment for protein absorption.